I think to get the best flavor, you go for a slow boil.
Turn a pot of cold water on simmer for 30 minutes.
Then build it up to medium for 20 minutes until it starts to boil.
Then back it down to simmer. Add 4 parts ice cubes to shock it.
Then gradually increase the temperature to high, until you have a full rolling boil.
Drop the temp, again, but this time to medium.
Let boil until the liquid has been reduced by half.
If it sticks to the back of a spoon, it's just right.
Now you have a perfect pot of boiled water. Proceed with the recipe as directed.
True story.